1. Field of the Invention
The present invention relates to a color processing apparatus that is configured to simulate a print product output by a printer on a monitor, and to a method for the same.
2. Description of the Related Art
A print product that is printed using a printer or the like is output assuming that the print product is observed under illumination having a color temperature of 5000K, which is termed D50. Thus, when the print result is simulated in advance using a monitor of a personal computer or the like, processing is executed by assuming that the print product is observed under a 50K illumination. This type of simulation is termed a “soft proof” and the processing is executed using a color matching system (hereinafter referred to as “CMS”). There is also a technique for simulating the appearance of color in a print product when using illumination other than D50 (Japanese Patent Application Laid-Open No. 9-46535). Although the accuracy of these methods is affected by a profile stating the characteristics of the print media, the printer or the monitor, which is termed the color profile, or the characteristics of the engine executing the CMS, the approximate print result can be reproduced on the monitor.
On the other hand, there is a technique of reproducing the color of a fabric on a monitor using computer graphics (CG) (Japanese Patent Application Laid-Open No. 2007-26049). This technique effectively creates a highly accurate bidirectional reflectance distribution function (BRDF) of the fabric using measurement data obtained from one incidence direction, and uses the bidirectional reflectance distribution function to execute shading processing.
However the impression when viewing the actual print product does not only depend on the color, but also is considerably affected by the gloss characteristics of the colorant forming the print product. Therefore, a strange impression often results when the print product is compared with the result of a simulation on a monitor. In other words, a simulation which is closer to the actual object requires not only color but also the gloss characteristics to be simulated at the same time.
When reproducing gloss using a reflection model in conventional CG such as a Phong Model or a Lambert Model, there is the problem that the intensity or color of the glossiness, which varies due to differences in colorants, such as bronzing cannot be reproduced on a monitor. When a CG model is used, this is due to the fact that the color of the gloss depends on the whiteness or on the color of the light source, and is normally uniform. Bronzing is a phenomenon in which a color is created in reflection due to diffuse reflection of illumination light from the print surface and appears as a metallic gloss such as an iridescent color which is different to the original printed color depending on the angle of view.